Abstract：
In view of the large deformation of extra-large section tunnels under high ground stress, a concept of observational design and construction, which consists of pre-design, information feedback, modification and verification test, is adopted based on the construction of the Daliang tunnel on the second line of Lanzhou-Xinjiang railway. By analyzing deformation of the monitored section and evolution of loose zone as well as internal force of support, the relative countermeasures are taken in tunnel design and construction, such as strengthening the primary support intensity and stiffness, resisting and releasing the stress simultaneously, reserving the time and space for stress release, construction with short bench method, and strengthening the locking bolts at the steel frame foot, by which the tunnel deformation is effectively controlled.
2013, Vol. 50 